A fan frame structure is as shown in FIG. 1. Its frame 10 has an accommodation space 11, and there is a bottom base 12 therein. A shaft tube seat 13 is disposed centrally on the bottom base 12 so that a fan motor and fan blades (not shown) can be fixedly mounted on the bottom base 12 and are located in the accommodation space 11. The bottom base 12 and the inner wall of the accommodation space are connected by a plurality of support arms 14 so as to integrally integrate the bottom base 12 and the frame.
As the conventional fan frame is integrally formed by die casting with metal material (i.e. aluminum), the disadvantages arise therefrom are as follows:
High material cost: The cost of metal material is certainly far higher than the cost of plastic material, adding that the prices of metal materials keep skyrocketing in recent years and further keeping the price of the metal fan frame integrally formed by die casting at a high level.
Quality issue: If a fan frame is entirely made of plastic material and the support arms of the bottom base are too flimsy and prone to breakage, the quality issue will be resulted.
High cost of mold: For sake of meeting various environment requirements for heat dissipation, cooling fan may need to replace fan motor with different power while not changing the size of the frame. As a result, many specifications actually provide a common frame size, and the only difference is the size of the bottom base. However, the conventional frame is integrally formed by die casting. Building a new mold for just size change of the bottom base becomes inevitable and is not cost-effective.
Difficult material management: In response to the assembling requirement of fan motors with assorted powers, the specifications and types of fan frames become more and more complicated, the stocked materials and parts are plentiful, and large warehousing space is demanded, all causing the difficulty of warehousing management.